Flange joints are generally used for connecting pipes together end-on-end. They require that a collar is at the ends of both the pipes to be joined together, typically e.g. a collar that is substantially perpendicular to the longitudinal axis of the pipe, on which collar the flange part rests. The collars of the pipe sections to be joined together remain between the flanges. The flanges are provided with apertures, through which tightening means, such as screws or bolts, are arranged and the joint is tightened with nut means. There are a number of alternatives for forming the collar. One typical method is presented in U.S. Pat. No. 4,905,492, wherein the collar is formed in two stages. The end of the pipe is initially expanded to an angle of approx. 35-40 degrees and after that with a second expanding means to an angle of approx. 90 degrees relative to the longitudinal direction of the pipe. Known from publication WO2006045887 is a pipe joint, which is formed from the end portions of the pipe sections to be joined together, said end portions having a collar preferably protruding substantially perpendicularly, and from flange parts placed on different sides of the collars relative to the junction and tightened with applicable fixing means, such as with screws and nuts. In the publication the flange part has been arranged to be substantially adaptable against the shoulder of the collar, most suitably its back surface, at least when the joint is being tightened. With the solution according to the publication straight pipe joints can be effectively formed.
A need has arisen to form pipe joints by means of which small displacements, e.g. 0-10 degrees, can be brought about in the joint. This sets requirements for, inter alia, the flange part arrangement of the joint.
The aim of the present invention is to achieve a completely new type of solution for a pipe joint, by means of which small angular displacements can be effectively brought about in a joint. Another aim is to achieve a pipe joint in which angular displacements can be brought about in connection with the collaring of the ends of the pipe sections. Yet another aim is to achieve an easily installable solution for a pipe joint, in which angular displacements can be adjusted, if necessary, in the installation phase. One aim of the invention is also to achieve a flange part arrangement that can be effectively applied in pipe joints that have a collar.